U.S. patent number 6,431,249 [Application Number 09/626,988] was granted by the patent office on 2002-08-13 for device for damping movement of telescopic guards.
This patent grant is currently assigned to P.E.I. Protezioni Elaborazioni Industriali S.r.l.. Invention is credited to Giorgio Tabellini.
United States Patent |
6,431,249 |
Tabellini |
August 13, 2002 |
Device for damping movement of telescopic guards
Abstract
A device for damping movement of a telescopic guard including a
plurality of box-shaped cover elements which slide inside each
other in a defined direction. A plurality of leaf springs
respectively connect the rear edges of the box-shaped elements to
the rear edges of adjacent box-shaped elements. A guide rod is
connected to each box-shaped element and is slidably connected to
the adjacent box-shaped element. The guide rod slides in a friction
element attached to an adjacent box-shaped element. Two circular
bellows are fitted around the rod.
Inventors: |
Tabellini; Giorgio (Sasso
Marconi, IT) |
Assignee: |
P.E.I. Protezioni Elaborazioni
Industriali S.r.l. (Bologna, IT)
|
Family
ID: |
11344165 |
Appl.
No.: |
09/626,988 |
Filed: |
July 27, 2000 |
Foreign Application Priority Data
|
|
|
|
|
Jul 30, 1999 [IT] |
|
|
BO99A0436 |
|
Current U.S.
Class: |
160/222; 160/202;
160/220; 160/223 |
Current CPC
Class: |
B23Q
11/0825 (20130101); B23Q 2011/0808 (20130101) |
Current International
Class: |
B23Q
11/08 (20060101); E06B 003/12 () |
Field of
Search: |
;160/197,220,221,222,223,224,219,DIG.2 ;267/85,109,139 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
7137781 |
|
Nov 1972 |
|
DE |
|
290822 |
|
Nov 1988 |
|
EP |
|
1286248 |
|
Oct 1998 |
|
IT |
|
Primary Examiner: Lev; Bruce A.
Attorney, Agent or Firm: Fay, Sharpe, Fagan, Minnich &
McKee, LLP
Claims
What is claimed is:
1. In combination with a telescopic guard device comprising a
plurality of associated box-shaped cover elements that
telescopically slide inside each other along a defined path, a
damping device comprising: a plurality of elastic means which
respectively connect each associated box-shaped element to an
adjacent smaller associated box-shaped element, said elastic means
being fixed to the rear edge of each associated box-shaped element
and to the rear edge of the adjacent smaller associated box-shaped
element.
2. The device according to claim 1, further comprising a plurality
of guide rods that respectively connect each associated box-shaped
element to the adjacent smaller box-shaped element.
3. The device according to claim 2, wherein each of said plurality
of guide rods has a first end rigidly connected to the associated
box-shaped element and a second end that has a stop surface
designed to engage with the smaller adjacent associated box-shaped
element to determine a fully extended position of the smaller
adjacent associated box-shaped element relative to the associated
box-shaped element.
4. The device according to claim 3, wherein each of the plurality
of guide rods comprises damping means to absorb shocks between the
guide rod and the box-shaped elements connected by the guide
rod.
5. The device according to claim 3, wherein each adjacent smaller
associated box-shaped element comprises at least one friction
element engaged with the guide rod that is connected to the
adjacent smaller associated box-shaped element.
6. The device according to claim 2, wherein each of the plurality
of guide rods comprises damping means to absorb shocks between the
guide rod and the box-shaped elements connected by the guide
rod.
7. The device according to claim 6, wherein the damping means
comprise a first circular bellows made of plastic and fitted around
the guide rod at a first end and a second circular bellows fitted
around the rod at its second end.
8. The device according to claim 7, wherein each adjacent smaller
associated box-shaped element comprises at least one friction
element engaged with the guide rod that is connected to the
adjacent smaller associated box-shaped element.
9. The device according to claim 6, wherein each adjacent smaller
associated box-shaped element comprises at least one friction
element engaged with the guide rod that is connected to the
adjacent smaller associated box-shaped element.
10. The device according to claim 2, wherein each adjacent smaller
associated box-shaped element comprises at least one friction
element engaged with the guide rod that is connected to the
adjacent smaller associated box-shaped element.
11. The device according to claim 10, wherein the friction element
comprises a material with high abrasion resistance which creates
sliding resistance between the friction element and the guide rod
in contact with the friction element.
12. The device according to claim 10, further comprising pressure
means for adjusting a pressure at which said friction element acts
on the guide rod in contact with the friction element.
13. The device according to claim 12, wherein the pressure means
for adjusting a pressure comprise a spring and means for adjusting
a thrust force of the spring on the friction element.
14. The device according to claim 2, wherein the elastic means
comprise at least one spring.
15. The device according to claim 1, wherein the elastic means
comprise at least one spring.
16. The device according to claim 15, wherein the spring is a leaf
spring.
17. The device according to claim 16, wherein the leaf spring
comprises two curved arms whose concave portions face each other
and which are hinged to each other at each end, the ends of the
arms being connected by a helical spring.
18. The device according to claim 15, wherein the spring comprises
a main annular body and two eyes forming an integral part of the
body and extending from both ends of the body on opposite sides of
an axis of symmetry of the body and parallel to the sliding
direction.
19. The device according to claim 15, wherein the spring is an
annular spring with a continuous preformed profile and an axis of
symmetry and consists of two semicircular portions with convexity
facing the inside of the profile and positioned on opposite sides
of the axis of symmetry, and two substantially straight portions,
positioned across the axis of symmetry, said semicircular portions
being joined to the respective straight portions by portions curved
in the shape of an S with concavities alternatively facing the
inside and outside of the annular spring.
20. The device according to claim 15, wherein the spring is a
composite spring and comprises an annular spring, with a continuous
preformed profile and an axis of symmetry parallel to the sliding
direction, and consisting of two semicircular portions with
convexity facing the inside of the profile and positioned on
opposite sides of the axis of symmetry, and two substantially
straight portions positioned across the axis of symmetry, said
semicircular portions being joined to the respective straight
portions by portions curved in the shape of a C with concavity
facing the outside of the annular spring, the composite spring
further comprising a helical metal spring forming a boundary inside
which the annular spring is inscribed.
21. In combination with a telescopic guard device comprising a
plurality of box-shaped cover elements that telescopically slide
inside each other along a defined path, a device for
interconnecting and damping relative movement of a first box-shaped
cover element and an adjacent smaller box-shaped cover element of
the telescopic guard device, said device comprising an elastic
member having a first portion fixedly secured to the first
box-shaped element and a second portion fixedly secured to the
second box-shaped element.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a device for driving and damping
telescopic guards of the type consisting of a plurality of
box-shaped elements.
Guards of this kind are used mainly to protect the slideways of
automatic machines, machine tools and robotized system by
preventing dirt, chippings, swarf and machining emulsions from
getting into and clogging up the contact areas of the
slideways.
The latest machines run at increasingly higher speeds and it is
therefore becoming more and more important to keep the slideways
clean and in perfect working order at all times.
The box-shaped elements are fitted with scrapers, usually, made of
an elastomer or plastic material. These scrapers, besides keeping
dirt and other foreign matter out of the gaps between adjacent
box-shaped elements, also permit the achievement of a satisfactory
seal.
Since the guard is connected to the moving part of the machine, the
box-shaped elements extend and retract at the same speed as that at
which the machine moves. This speed can be very high and
considering their size and weight, the box-shaped elements, when
they reach the fully extended position, knock against each other
with considerable force. Such shocks must obviously be avoided not
only because of the wear and eventual damage they cause to the
guard but also to prevent counterblows on the moving machine parts
and, last but not least, to reduce noise.
It is therefore essential to provide damping devices between the
box-shaped elements.
A damping device designed for this purpose is described in utility
model patent publication DE-U-7137781. In this publication, the
damping device is made by simply applying to the back of the
scraper, where it comes into contact with the smaller, adjacent
box-shaped element a strip of synthetic cellular material. Another
type of damping device for the box-shaped elements of a telescopic
guard made from a strip of material different from that of the
scraper is described in patent publication EP-B-290822.
However, with damping devices of this kind, shocks are still
possible on account of the high speeds reached by the moving
machine parts, the weight of the boxshaped elements and the limited
deformability of the strips of synthetic material.
Moreover, when the guards reach the fully extended position, the
box-shaped elements stop, passing from a very high speed to zero
speed in a very short space of time. They are therefore subjected
to a high deceleration rate which can have negative effects on the
moving machine parts.
Italian patent No. 012862248, in the name of the same Applicant as
the present, describes a damping device equipped with deformable,
elastic arms designed to damp the impact between two adjacent
box-shaped elements when these are being extended.
Mechanical devices designed to simultaneously open all the
box-shaped elements making up the telescopic guards have also been
made in an attempt partly solve the problem of shocks. These
devices consist either of a series of chains acting on hooking
elements located in each single box-shaped element or complex
telescopic joints located in the box-shaped elements
themselves.
SUMMARY OF THE INVENTION
The principal aim of the present invention is to overcome the
disadvantages of prior art through a new device for driving and
damping the box-shaped elements of telescopic guides that is
capable of simultaneously driving all the box-shaped elements while
providing a gradual and effective damping action and that is simple
and economical to make.
BRIEF DESCRIPTION OF THE DRAWINGS
The technical features of the present invention, in accordance with
the above mentioned aims, are set out in the claims herein and the
advantages more clearly illustrated in the detailed description
which follows, with reference to the accompanying drawings, which
illustrate preferred embodiments of the invention without
restricting the scope of the inventive concept and in which:
FIG. 1 is a perspective view from above, with some parts cut away,
of a telescopic guard equipped with the device disclosed by the
present invention;
FIG. 2 is a view from below of the telescopic guard illustrated in
FIG. 1, in a closed configuration.
FIG. 3 is a view from below of the telescopic guard illustrated in
FIG. 1, in an open configuration.
FIG. 4 is a perspective view from above of a detail of the device
illustrated in FIG. 1;
FIG. 5 is a perspective view of the telescopic guard equipped with
the damping device made according to another embodiment of the
invention illustrated in FIG. 1;
FIG. 6 is a schematic perspective view of a detail from FIG. 4;
FIGS. 7 and 8 are bottom views of another embodiment of the
telescopic guard illustrated in FIG. 1, shown in the closed
configuration and in the open configuration, respectively;
FIGS. 9 and 10 are bottom views of another embodiment of the
telescopic guard illustrated in FIG. 1, shown in the closed
configuration and in the open configuration, respectively;
FIGS. 11 and 12 are bottom views of another embodiment of the
telescopic guard illustrated in FIG. 1, shown in the closed
configuration and in the open configuration, respectively;
FIGS. 13 and 14 are bottom views of yet another embodiment of the
telescopic guard illustrated in FIG. 1, shown in the closed
configuration and in the open configuration, respectively;
FIG. 15 is a perspective view from above of a detail of the device
illustrated in FIGS. 9 and 10;
FIG. 16 is a perspective view from above of a detail of the device
illustrated in FIGS. 11 and 12.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the accompanying drawings, the numeral 20
indicates as a whole a device for driving and damping a telescopic
guard, labeled 1 as a whole, used to protect the slideways of
automatic machines, machine tools and robotized systems, of known
type and therefore not illustrated.
As shown in FIG. 1, the telescopic guard, comprising a plurality of
box-shaped elements 2, is attached at one end to a fixed part 30 of
the machine and, at the other end, to a moving part 40 of the
machine, and can be extended or retracted in the direction of the
arrow F.
For clarity, some parts of the telescopic guard 1 and of the device
20 have been cut away and others are illustrated as
transparent.
The box-shaped elements 2 making up the guard are of known type
made, for example, of steel, and usually have at least one
horizontal wall 2a, two vertical walls 2b, a front edge 2c and a
rear edge 2d.
With the exception of the box-shaped elements 2 at the ends of the
telescopic guard 1, each element 2 borders on two other box-shaped
elements, one larger and the other smaller than it. The elements 2
slide inside one another in telescopic fashion in a direction F,
moving between a first position in which the guard 1 is closed or
fully retracted, to a second position in which the guard 1 is open
or fully extended. These end positions of the telescopic guard 1
correspond to the end positions of the machine which the guard 1 is
fitted to.
Close to the rear edge 2d of each box-shaped element 2, there is a
scraping device 3 comprising a section 4 and a scraping element 5,
both of known type.
With reference to the accompanying drawings, each box-shaped
element 2 is connected to the box-shaped element 2 adjacent to it
by an elastic element, labeled 6 as a whole, fitted close to the
rear edge 2d of each box-shaped element 2. In particular, as shown
in FIGS. 1, 2 and 3, the elastic elements 6 consist of leaf springs
61.
Again with reference to FIGS. 1, 2 and 3, two guide rods 7 connect
each box-shaped element 2 to the box-shaped element 2 adjacent to
it. A first end 7a of each rod 7 is rigidly connected to a
box-shaped element 2, while a second end 7b has a stop surface 8.
The latter is made in such a way that it engages with the smaller
adjacent box-shaped element 2 to determine a fully extended
position of the two box-shaped elements 2 relative to each
other.
During the relative movement of two adjacent box-shaped elements 2,
the rod 7 that is integral with the larger of the two box-shaped
elements 2 slides into a supporting bush 9 fixed to the rear edge
2d of the smaller of the two box-shaped elements 2.
Inside it, the bush 9 has a friction element 10 consisting, for
example, of a part 11 made of synthetic or natural rubber or of
another material with a high abrasion resistance.
Each rod 7 is provided with damping means 12. In the embodiment
illustrated, these damping means comprise a first circular bellows
12a fitted round the rod 7 close to its first end 7a and a second
circular bellows 12b fitted close to the second end 7b of the rod
7.
The circular bellows 12a and 12b are made of synthetic material and
are fitted in such a way that they can slide freely along part of
the rod 7, on opposite sides of the rear edge 2d of the box-shaped
element 2 crossed by the rod 7.
The rods 7 of the different box-shaped elements 2 are offset from
each other crossways so as not to interfere with each other during
the opening and closing movements of the guard 1.
Each box-shaped element 2 is equipped with rolling-contact bearings
13 fitted on the edge 2d, close to the ends of the edge 2d itself,
which are designed to support the telescopic guard 1 and enable it
to run on the slideways of the machine, which are not
illustrated.
The rear edge 2d of each box-shaped element 2 also has a plurality
of holes 14 allowing the passage of the rods 7 of the box-shaped
elements 2 larger than it so that the size of the telescopic guard
1 when it is fully retracted, that is to say, closed, is not
determined by the length of the rods 7 but by the space occupied by
the leaf springs 61 lengthways when they are flat against each
other.
In the embodiment illustrated in FIGS. 7 and 8, the elastic element
6 that connects the adjacent boxshaped elements 2 consists of a
plastic spring 62 comprising a main body 63 made and designed to
operate, at least during the opening of the box-shaped elements 2,
like a pair of ordinary leaf springs positioned with their concave
portions facing each other, and two eyes 64 forming an integral
part of the body 63 and extending from both ends of the body 63 on
opposite sides of an axis of symmetry A of the body 63 itself
parallel to the above mentioned direction F. The eyes 64 constitute
shock absorbing elements that come into operation by compression
when the box-shaped elements 2 of the guard 1 are retracted.
In the embodiment shown in FIGS. 9 and 10, the elastic connecting
element 6, illustrated in more detail in FIG. 15, consists of an
annular spring 65 formed by a substantially rectangular plastic
section 70, with a continuous preformed profile P1 and an axis of
symmetry A', and consisting of two semicircular portions 71 with
convexity facing the inside of the profile P1 and positioned on
opposite sides of the axis of symmetry A', and two substantially
straight portions 72, positioned across the above mentioned axis of
symmetry A', and designed to be attached to the rear edges 2d of
two adjacent box-shaped elements 2. The semicircular portions 71
are joined to the respective straight portions 72 by portions 73
curved in the shape of an S with concavities alternately facing the
inside and outside of the annular spring 65 itself.
In the embodiment shown in FIGS. 11 and 12, each of the elastic
elements 6 connecting adjacent box-shaped elements 2, illustrated
in more detail in FIG. 16, consists of a composite spring 66 made
by assembling an annular spring 74 similar to the one described
above, labeled 65 in FIGS. 9, 10 and 15, and a helical metal spring
67 closed in a loop round the annular spring 74 itself and forming
a boundary P2 whose shape varies according to the movements of the
box-shaped elements 2 relative to each other and inside which the
annular spring 74 is inscribed. Looking in more detail, the annular
spring 74 is formed by a substantially rectangular plastic section
77, with a continuous preformed profile P2 and an axis of symmetry
A", and consisting of two semicircular portions 75 with convexity
facing the inside of the profile P2 and positioned on opposite
sides of the axis of symmetry A", and two substantially straight
portions 76, which are shorter than the above mentioned straight
portions 72 of the spring 65, said portions 76 being positioned
opposite each other across the above mentioned axis of symmetry A",
and designed to be attached to the rear edges 2d of two adjacent
box-shaped elements 2. The semicircular portions 75 are joined to
the respective straight portions 76 by portions 78 curved in the
shape of a C with concavity facing the outside of the annular
spring 74 itself.
The helical spring 67 and the plastic spring 65, together forming
the composite spring 66 are joined together at two or more points
in such a way that their actions are combined during the movements
of the boxshaped elements 2 relative to each other. These
connecting points consist of blocks extending from the outer
surface of the annular spring and each having a hole in it through
which the helical spring 67 can pass.
In the embodiment shown in FIGS. 13 and 14, the elastic connecting
elements 6 consist of leaf springs 68, each comprising two curved
arms 69 whose concave portions face each other and which are hinged
to each other at each end, the ends of the arms 69 being connected
by a helical spring 67 providing additional spring action during
the movements of the box-shaped elements 2 relative to each
other.
In the present description, reference is made to generic elastic
elements 6 unless one or more of the embodiments of the elements
described above, labeled 61, 62, 65, 66 and 68, is being
specifically described.
During use, let us assume that the telescopic guard 1 starts from
the position illustrated in FIG. 2, 7, 9 or 11 referred to above as
the fully retracted or closed position of the guard 1.
As shown in these figures, the box-shaped elements 2 are retracted
and almost entirely nested inside each other. The box-shaped
elements 2 slide relative to each other on appropriate shoes (not
illustrated).
In this closed position, the elastic elements 6 are at least partly
compressed so that when the moving part 40 of the automatic
machine, machine tool or robotized system starts moving, the
box-shaped element 2 to which the moving part 40 is connected is
dragged along with it and the telescopic guard 1 thus starts
opening, the opening action being facilitated also by the
simultaneous extension of the elastic elements 6. The elastic
elements 6 cause all the box-shaped elements 2 to which they are
connected to be simultaneously extended in the direction of the
arrow F.
Besides this opening action, the simultaneous extension of the
box-shaped elements 2 is also facilitated by the combined action of
the rods 7 and the friction elements 10 fitted inside the bushes 9.
The sliding friction caused by the contact between the surface of
the rubber part 11 of the friction element 10 and the surface of
the rod 7 as the rod 7 slides inside the corresponding bush 9 (see
FIG. 4) creates a driving action on the friction element 10 and on
the bush 9 to which it is attached. This driving action is
transmitted by the bush 9 to the box-shaped element 2 to which it
is attached and thus helps to pull the boxshaped element 2 out of
the element adjacent to it.
FIG. 3 illustrates four box-shaped elements 2 in an almost fully
extended position.
For each rod 7, the circular bellows 12b placed between the stop
surface 8 and the bush 9 provides an effective damping action
thanks not only to the compression of the air inside it but also to
the shape of the bellows 12b and the material it is made of.
Therefore, when the telescopic guard 1 is extended, the box-shaped
elements 2 are prevented from knocking against each other.
In the almost fully extended condition, each of the elastic
elements 6 is stretched and thus has a certain amount of
accumulated elastic potential energy. This elastic energy is
returned by the elastic elements 6 to the box-shaped elements 2
from the moment the guard starts retracting again following the
motion of the moving part 40 of the machine. The return action
exerted by the elastic elements 6 during the reclosing movement
tends to move the box-shaped elements 2 towards each other
again.
As they return to the closed position illustrated in FIG. 2, 8, 10,
12 and 14, the box-shaped elements 2 transmit to the rods, again
through the friction element 10, a pushing action similar to the
extending action received by the rods 7 during the opening
movement.
The circular bellows 12a fitted close to the area where each rod 7
is attached to the corresponding boxshaped element 2 is compressed
between the two rear edges 2d of two adjacent box-shaped elements 2
moving towards each other when the telescopic guard 1 is
retracting. The resulting action is similar to that described above
that occurs when the telescopic guard 1 is being extended.
The compression of the bellows 12a provides an effective damping
action which prevents the box-shaped elements 2 from knocking
against each other. The elastic elements 6 contribute to the
damping action by compressing and thus absorbing, in the form of
elastic potential energy, part of the kinetic energy possessed by
the box-shaped elements 2 as they move towards each other,
accumulating this energy so that it can be used later, when the
telescopic guard 1 next opens.
From the above description, it is clear that during operation of
the telescopic guard 1, the damping function is the result of a
combination of different factors.
The damping capability of the device is much higher than that of
known devices of this kind. The damping action is developed
gradually and effectively over a relatively long stroke.
In another embodiment of the device, illustrated in FIG. 6, the
friction element 10 comprises a pressure element 16, actuated by a
spring 17 and acting on the part 11 in such a way as to push it
against the rod 7. The contact pressure between the part 11 and the
surface of the rod 7 generates a friction component which opposes
the relative motion between the rod 7 itself and the different
parts attached to the friction element 10. The contact pressure
between the part 11 and the rod can be adjusted using a screw 18
which controls the thrust force of the spring 17.
It should be noted that the friction element 10 acting on the rods
7 has a stabilizing effect on the telescopic guard 1, thus
preventing vibrations, at both high and low speeds of the
box-shaped elements 2 retracting and extending relative to each
other.
In a preferred embodiment illustrated in FIG. 5, the drive and
damping device 20 disclosed by the present invention further
comprises a damping element 15 made of plastic and fitted to the
rear edge 2d of each boxshaped element 2 at the corner between the
horizontal wall 2a and the vertical wall 2b of the element 2. To
facilitate the bending of the damping element 15 on said corner,
the device 15 has a lightening groove 15a extending lengthways
parallel to the side of the guard.
The invention described can be subject to modifications and
variations without thereby departing from the scope of the
inventive concept. Moreover, all the details of the invention may
be substituted by technically equivalent elements.
* * * * *